Sites - Important Bird and Biodiversity Areas (IBAs)
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Moyowosi - Kigosi Game Reserves
31o 30.00' East 4o 40.00' South
1,000 - 1,300m
Year of IBA assessment
Site description This site, situated in the interior of western Tanzania, is a vast wetland system of limited access, even in the dry season. During times of peak flood the flood-plains of the Malagarasi, Moyowosi, Nikonga, Kigosi and Gombe rivers cover nearly 1,000,000 ha and the permanent swamps along the margins of the rivers and lakes extend over 350,000 ha. The riverine vegetation is dominated by Borassus and Phoenix palms with stands of Acacia woodland along the margins of the flood-plain. The higher ground between the rivers is cloaked in Brachystegia–Julbernardia woodland with patches of groundwater forest in areas with a high water-table. The Moyowosi and Malagarasi rivers both rise in the highlands of Burundi, while the Nikonga, Kigosi and Gombe rivers drain the central plateau south and south-east of Lake Victoria. These rivers join to the east of Uvinza and drain into Lake Tanganyika, 40 km south of Kigoma. The central railway between Tabora and Kigoma crosses the southern edge of the wetland, separating it (except during wet years when the whole area is inundated) from the Ugalla river wetland system (TZ019).
Key Biodiversity See Box for key species. Little is known of the avifauna in this part of Tanzania. During January 1995, waterbirds in the lakes and swamps south of the confluence of the Moyowosi and Kigosi rivers were counted. The difficulties of working such a vast area without boats and aircraft meant that numbers of many species were probably seriously under recorded, but included Mesophoyx intermedia (263), Ardea goliath (42), Ardea purpurea (158), Ardeola ralloides (298), Ardeola rufiventris (48), Thalassornis leuconotus (63) and Sterna nilotica (76). Surveys of Balaeniceps rex have estimated 493 ±86 at Moyowosi (1990), 1,867 ±891 at Kigosi (1990) and 168 ±78 outside the reserves (1990). A 1992 estimate of 2,489 birds is considered rather high. Only 44 Gallinago media were recorded in 1995, but the real population of this globally threatened species is probably far higher. Three species of the Zambezian biome have been recorded (see Table 3).
Non-bird biodiversity: Among mammals, populations of Loxodonta africana (EN) have declined from an estimated 27,279 to 1,400; Lycaon pictus (EN) still occurs.